Abstract & Overview
Mixed residues containing cowdung and Azolla pinnata (1 : 0.4) can produce maximum quantity of biogas as compared to other residues. After 15 days digestion of the mixed residue in a batch system, total solid reduction of about 20.35% and gaseous energy recovery of about 20.23% as methane could be achieved. Digested slury maximized the growth of both phyto- and zoo- plankton, the numbers being 24 x 10 6 /L and 128x10 2 /L respectively, thereby indicating its potential as a Fish pond fertilizer. Conventional fish-feed (20%) alongwith the digested Azolla slurry was observed to be most suitable as fish-feed.